The prospects of cancer immunotherapy rely upon the identification of tumor associated antigens which can be recognized by the immune system. Specifically, target antigens eliciting T cell-mediated responses are of critical interest. This comes from evidence that cytotoxic T lymphocytes (CTLs) can induce tumor regression both in animal models (Kast W. et al (1989) Cell 59:6035; Greendberg P. (1991) Adv. Immunol. 49:281) and in humans (Boon T. et al. (1994) Annu. Rev. Immunol. 12:337). Antigens recognized by CTLs consist of peptides originating from endogenous proteins presented in association with Major Histocompatibility Complex (MHC) molecules.
The first such human tumor associated antigen characterized was identified from a melanoma. This antigen (originally designated MAGE 1) was identified using CTLs isolated from an HLA A1+melanoma patient to screen HLA A1 target cells transfected with tumor DNA (van der Bruggen P. (1991) Science 254:1643; said tumor associated antigens are now designated MAGE-A1, MAGE-A2, etc.—for purposes of this application the older designation will be adopted). Interestingly, MAGE 1 was found to belong to a family of at least 12 closely related genes located on the X chromosome (de Plaen, B. et al. (1994) Immunogenetics 40:360). The nucleic acid sequence of the 11 additional MAGE genes share 65-85% identity with that of MAGE-1 (de Smet, C. et al. (1994) Immunogenetics 39: 121). Both MAGE 1 and 3 are present in normal tissues, but expressed only in the testis (de Plaen, E. et al. (1994) Supra; de Smet, C. et al. (1994) Supra; Takahashi, K. et al. (1995) Cancer Res. 55:3478; Chomey, P. et al. (1995) Immunogenetics 43:97). These initial results have subsequently been extended with the identification of new gene families (i.e. RAGE, BAGE, GAGE), all of which are typically not expressed in normal tissues (except testis) but expressed in a variety of tumor types.
MAGE-1 and MAGE-3 are expressed in 48% and 76% of metastatic melanomas respectively (Brasseur, F. et al. (1995) Int. J. Cancer 63:375), 35% and 30% of non-small cell lung cancer (“NSCLC”; Weynants, P. et al. (1994) Int. J. Cancer 56:826), 27% and 48% of head and neck, squamous cell carcinomas (Eura, M. et al. (1995) Int. J. Cancer 64:304), 62% and 57% of esophageal squamous cell carcinomas (Inoue, H. et al. (1995) Int. J. Cancer 63:523), and 21% and 35% of bladder transitional cell carcinomas (Patard, J.-J. et al. (1995) Int. J. Cancer 64:60). They are also expressed (albeit less frequently) in tumors of other histological types such as breast tumors, soft tissue sarcomas and prostatic carcinoma (Brasseur, F. et al. (1992) Int. J. Cancer 52:839; Van der Eynde et al. (1995) Curr. Opin. Immunol. 7:674). The MAGE 3 gene is also expressed in colorectal carcinoma.
A number of immunogenic epitopes/peptides derived from MAGE proteins (in particular MAGE 1, 2 and 3) have been identified and characterized (reviewed in van der Eynde, B. J. and Boon, T. (1997) Int. J. Chem. Lab Res. 27:81). CTLs isolated from two melanoma patients were found to recognize MAGE-1 derived peptides presented in association with HLA-A1, B37 or Cw16 (Traversi, C. et al (1992) J. Exp. Med 176:1453; Tanzarella, S. et al. (1999) Cancer Res. 59:2668; van der Bruggen, P. et al. (1994) Eur. J. Immunol. 24:2134). In particular, the nonapeptide EADPTGHSY (amino acids 161-169 of MAGE 1) was demonstrated to be presented to cells of the immune system in association with the MHC class 1 molecule HLA-A1 (Traversi, C. et al. (1992) Supra). Synthetic peptides utilized to stimulate T cells have also facilitated the identification of a MAGE 1 epitope presented by HLA-A24 (Fujie, T et al. (1999) Int. J. Cancer 80:169).
It has also been demonstrated that MAGE-3 directs the expression of a number of antigens recognized by CTLs. For example, the nonapeptide EVDPIGHLY (amino acid 168-176 of MAGE 3) is recognized in association with the MHC class 1 molecule HLA-A1 (Gaugler, B. et al. (1994) J. Exp. Med 179:921); the decapeptide MEVDPIGHLY (amino acids 167-176) in association with the MHC class 1 molecules HLA-B44.02 and HLA-B44.03 (Herman, J. et al. (1996) Immunogenetics 43:377); the nonapeptide FLWGPRALV (amino acids 271-279) in association with the MHC class 1 molecule HLA-A2.01 (van der Bruggen, P. et al. (1994) Eur. J. Immunol 24:3038). Furthermore, van der Bruggen and colleagues have identified six additional MAGE-derived epitopes that are presented to CTL in association with HLA-A3, A28, B7, B53, Cw2 and Cw3 (Chaux, P. et al. (1999) J. Immunol 163:2928; Luiten, R. et al. (2000), Tissue Antigens, 55: in press). Interestingly, it has recently been observed that an epitope of MAGE 1 previously identified as an epitope recognized by CTL in association with HLA-A1 can also be presented to CTL in association with both HLA-B3501 and B3503 (van der Bruggen, P. et al. (2000), submitted).
The present invention discloses novel polypeptides comprising several distinct MAGE-specific antigen epitopes selected from different (i.e. discrete) members of the MAGE protein family, nucleic acids coding therefor, recombinant viruses and/or cells comprising said nucleic acids, compositions of the aforementioned agents, and their advantageous use in generating MAGE-specific immune responses.